1. Field of the Invention
The present invention relates to a method of detecting angular velocity of an angular velocity sensor including a vibrating body.
2. Description of the Related Art
Conventionally, an angular velocity sensor including a vibrating body is used for detecting a rotation of a vehicle or a slip of a vehicle. For example, in a vehicle stability control system or a four-wheel steering angle control system, a slip of a vehicle is detected based on an angular velocity signal detected by an angular velocity sensor. When an abnormality of the vehicle such as a slip is detected, a brake is controlled so as to enable a driving safety.
JP-A-2008-58212 discloses an angular, velocity sensor that detects an angular velocity signal by vibrating a vibrating body in a driving-axis direction and detecting a signal generated in accordance with a displacement of the vibrating body in a detecting-axis direction crossing the driving-axis direction.
The above-described angular velocity sensor executes a high-speed analog-digital conversion process for a sine wave at a resonant frequency of the vibrating body and executes a digital signal process so that a high-accuracy angular velocity signal can be obtained.
However, because the above-described angular velocity sensor requires a high-speed analog-digital converter, the above-described angular velocity sensor is difficult to be configured by an inexpensive microcomputer. Thus, the above-described angular velocity sensor may not meet a requirement of a price reduction.